This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A307757 #45 May 07 2021 05:09:48
%S A307757 1,-1,0,0,-1,0,2,-2,0,2,-2,0,4,-4,0,4,-5,0,8,-8,0,8,-10,0,14,-15,0,16,
%T A307757 -18,0,24,-26,0,28,-32,0,42,-44,0,48,-54,0,68,-72,0,80,-88,0,108,-115,
%U A307757 0,128,-140,0,170,-180,0,200,-218,0,260,-276,0,308,-333,0,392,-416,0,464
%N A307757 Expansion of Product_{k>=1} 1/(1 + x^k/(1 + x^(2*k))).
%t A307757 m = 70; CoefficientList[Series[Product[1/(1 + x^k/(1 + x^(2*k))), {k, 1, m}], {x, 0, m}], x] (* _Amiram Eldar_, May 07 2021 *)
%o A307757 (PARI) N=66; x='x+O('x^N); Vec(1/prod(k=1, N, 1+x^k/(1+x^(2*k))))
%Y A307757 Cf. A309733, A327686, A327688.
%K A307757 sign
%O A307757 0,7
%A A307757 _Seiichi Manyama_, Sep 22 2019